Ropidoxuridine and Whole Brain Radiation Therapy in Treating Patients With Brain Metastases

Inclusion Criteria: * Patients must have histologically confirmed malignancy with brain metastases and are being recommended palliative WBRT * Life expectancy of greater than 2 months to allow completion of study treatment and assessment of dose-limiting toxicity * Eastern Cooperative Oncology Group (ECOG) performance status =\< 2 (Karnofsky \>= 60%) * Leukocytes \>= 3,000/mcL * Absolute neutrophil count \>= 1,000/mcL * Platelets \>= 100,000/mcL * Calculated creatinine clearance \>= 45 mL/min/1.73 m\^2 * Total bilirubin: * If no known liver metastases: total bilirubin \< 1.5 x institutional upper limit of normal (ULN) * If known liver metastases, then: total bilirubin \< 2.5 x ULN * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\]) and alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase \[SGPT\]): * If no known liver metastases: AST/SGOT and ALT/SGPT both \< 2 x ULN * If known liver metastases, then: AST/SGOT and ALT/SGPT both \< 5 x ULN * Human immunodeficiency virus (HIV) positive (+) patients with CD4 counts \>= 250 cells/mm\^3 on anti-viral therapy are eligible for the study * Negative urine or serum pregnancy test result for females of child bearing potential only; Note: The effects of IPdR on the developing human fetus are unknown; for this reason and because radiation therapy is known to be teratogenic, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier meth…